In water jet cutting and other high pressure fluid applications it is often desirable to use flexible hose to convey the fluid. In applications where the pressure is ultra high as in those over 10,000 pounds per square inch, the hose is commonly constructed of a plastic liner surrounded by multiple layers of reinforcing material. Hose fittings are required to attach such a hose to another hose or to equipment such as intensifiers or nozzles.
An ultra high pressure hose fitting normally includes a barbed nipple which is pressed inside the liner tube of the hose. An outer sleeve is then swagged over the reinforcing layers of the hose and the nipple. The hose is thus clamped between the nipple and the sleeve and the nipple is held by the sleeve against axial motions. As pressure is applied to the hose a force is generated that tends to separate the barbed nipple from the hose permitting a leak. This tendency is resisted by the clamping force exerted by the sleeve. When the pressure is very high the clamping force must be increased. If the nipple is not increased in thickness it will be collapsed by the clamping force when high pressure is not present, when, for example, the intensifier is off. The thickening of the nipple results in a constriction of the bore at the fitting. The constriction produced becomes the limiting factor in the carrying capacity of the hose. Accordingly, a demand exists for an ultra high pressure hose fitting which does not constrict the hose but is able to withstand pressures in excess of 10,000 psi.